An important input for an elevator controller relates to the load, or number of passengers, in the elevator car. U.S. Pat. No. 4,330,836 granted May 18, 1982 to A. J. Donofrio, et al., relates to elevator cab load measuring, and contains a discussion of the desirability of monitoring car load, and the enhancement of elevator control derived therefrom. In the system disclosed in this patent, the elevator car is mounted on the frame by means of a plurality of elastomeric damped mount assemblies. There are, for example, six of the mount assemblies, and two of them will be equipped with force transducers which measure the car load.
U.S. Pat. No. 4,899,852 granted Feb. 13, 1990, to us discloses an elevator car mounting assembly wherein the car is suspended on the frame by a plurality of pendulum rods, one at each corner of the car. This patent briefly alludes to a load weighing assembly which is included in the mounting assembly.
Disclosure of the Invention
This invention relates to the preferred embodiment of the load weighing assembly generally disclosed in U.S. Pat. No. 4,899,852. The car is suspended in the frame by four pendulum rods, one at each corner of the car. One diagonally opposed pair of the pendulum rods will be equipped with the load weighing assembly of this invention. This allows for more accurate monitoring of the car load since there are only four load paths, and 50% of them will be monitored. In the prior art, only 33% or less of the load bearing paths were monitored. The load weighing assembly permits a single capacity transducer to be used over a wide range of elevator car weights. In general, the assembly includes a lever which presses on the transducer so that the length of the lever arm acts as a multiplier of the operating range of the load cell transducer.
It is therefore an object of this invention to provide an improved load weighing capability for an elevator car.
It is a further object of this invention to provide an elevator car load weighing assembly which can be used on a suspended car.
It is another object of this invention to provide an elevator car load weighing assembly of the character described which can utilize a common load transducer or load cell on elevator cars of different weights.
These and other objects and advantages of the invention will become more readily apparent from the following detailed description of a preferred embodiment thereof, when taken in conjunction with the accompanying drawings, in which: